This will cause your entire desktop environment to crash, leaving you with nothing but a wallpaper.

According to this bug report, the behaviour has been fixed in gnome-shell 3.4.2-9, which is, at this point, still in sid/unstable. So once more: do not upgrade gnome-bluetooth to 3.8.1-1 before gnome-shell 3.4.2-9 has entered the jessie/testing repositories.

In case you have accidentally upgraded and are now facing a useless desktop, switch to tty1 (Ctrl + Alt + F1), log in, and type the following:

After downgrading the packages, run sudo service gdm3 restart and log back in again. (If you’re using sysvinit, run sudo /etc/init.d/gdm3 restart.)

In order for this to work, you’ll need the stable repositories to be present in your /etc/apt/sources.list. If they’re not, first run sudo nano /etc/apt/sources.list (or another text editor) and make sure it contains the following line: